This is an on-going issue for me. It started when I ran the ubuntu updater and installed a 13.04 nightly build about 2 months ago. I didn't have time to fix it, so I let it go. About a week ago I downloaded the 13.04 release version. After a full fresh install, I still seem to have this issue. I can't understand why suddenly unity looks like this, even after I wiped my last ubuntu installation.
Is this something related to my gfx hardware, possibly?
btw, I should mention that this is the ONLY place in the entire system the gui looks like this. If I close the launcher and leave just the sidebar open it looks totally normal.